Fix import order which caused the wrong from_str to be in scope

Author: emberian

src/libstd/num/float.rs

@@ -946,8 +946,8 @@ impl Float for float {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use prelude::*;
+    use super::*;
 
     use num::*;
     use num;

src/libstd/num/int_macros.rs

@@ -547,8 +547,8 @@ impl ToStrRadix for $T {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use prelude::*;
+    use super::*;
 
     use int;
     use i16;

src/libstd/num/uint_macros.rs

@@ -430,8 +430,8 @@ impl BitCount for $T {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use prelude::*;
+    use super::*;
 
     use num;
     use sys;